In preparation for an examination, have students write the questions they expect will be on the test and then administer them to you orally during the class you use to prepare them for the examination. This will give you a sense of what they think is important, and them a sense of how exams are created. I once did this exercise in lieu of a mid-term, but realized too late that they had never really had any experience in constructing questions, and so it became rather difficult to grade them on the questions they created. As an in-class exercise, it works well and takes some of the edge off exam taking.